1. Field of the Invention
Embodiments of the invention relate to a display device, and more particularly, to a liquid crystal display device. Although embodiments of the invention are suitable for a wide scope of applications, it is particularly suitable for operating a liquid crystal display device in an extremely low temperature environment or an extremely high temperature environment, which are outside an operating temperature range of liquid crystal material.
2. Description of the Background Art
In general, a liquid crystal display device displays a desired image by individually supplying data signals based on image information to liquid crystal cells arranged in a matrix shape so as to control light transmittance through the liquid crystal cells. More particularly, the liquid crystal display devices have a liquid crystal panel with pixel units that are liquid crystal cells arranged in a matrix shape. The pixel units are driven by a driving circuit on the liquid crystal panel.
The liquid crystal display panel includes a color filter substrate, a thin film array substrate, and a layer of liquid crystal molecules positioned between the color filter substrate and the thin film array substrate. The color filter substrate and the thin film transistor array substrate are attached to each other by a seal pattern adjacent to the edge of the liquid crystal panel. Color filters and a black matrix for preventing light leakage between pixels are formed on the color filter substrate. Gate lines and data lines that cross each other to define the pixel units are formed on the thin film transistor. Switching elements that switch the pixel units are respectively formed adjacent to where the gate lines and the data lines cross each other.
Gate pads and data pads are formed at ends of the gate lines and the data lines, respectively, for electrical connection to the driving circuit. The driving circuit includes a gate driving unit that supplies a scanning signal to each of the gate pads of the liquid crystal panel, and a data driving unit that supplies image information to the data pads. The gate driving unit and the data driving unit are integrated as a plurality of integrated circuits (hereinafter, referred to as “IC”).
The liquid crystal display device that includes the above-described structure drives a layer of liquid crystal molecules with a signal applied to each pixel electrode so as to display an image. In general, the liquid crystal molecules can be driven within an operating temperature range of about −20° C. to about 60° C. When the liquid crystal panel is used in an environment in which the temperature is outside of the operating temperature range of the liquid crystal material, either a poor image or no image is displayed.
For example, a liquid crystal panel can be used as an aircraft display that displays important flight information to a pilot. The liquid crystal panel may not properly display the flight information when the environment temperature goes below −20° C. or above 60° C. More particularly, the liquid crystal material in the liquid crystal panel can not be properly driven in a low temperature environment of below −20° C. or in a high temperature environment of above 60° C. Because the liquid crystal panel can not be properly driven at such low temperatures or at such high temperatures, flight information on the aircraft display screen may not be discernable.
The environmental temperature in which a liquid crystal display can operate is limited according to the related art. Information within a displayed image can not be reliably provided on the liquid crystal panel when the temperature of the environment outside of the liquid crystal panel is not within the operating temperature range of the liquid crystal material in the liquid crystal panel. Thus, the related art liquid crystal display are limited to temperature environments within the operating temperature range of the liquid crystal material.